Probing a water channel near the A-ring of receptor-bound 1 alpha,25-dihydroxyvitamin D3 with selected 2 alpha-substituted analogues

The crystal structure of the vitamin D receptor (VDR) in complex with 1 alpha,25(OH)2D3 revealed the presence of several water molecules near the A-ring linking the ligand C-2 position to the protein surface. Here, we report the crystal structures of the human VDR ligand binding domain bound to selected C-2 alpha substituted analogues, namely, methyl, propyl, propoxy, hydroxypropyl, and hydroxypropoxy. These specific replacements do not modify the structure of the protein or the ligand, but with the exception of the methyl substituent, all analogues affect the presence and/or the location of the above water molecules. The integrity of the channel interactions and specific C-2 alpha analogue directed additional interactions correlate with the binding affinity of the ligands. In contrast, the resulting loss or gain of H-bonds does not reflect the magnitude of HL60 cell differentiation. Our overall findings highlight a rational approach to the design of more potent ligands by building in features revealed in the crystal structures.     

Understanding treatment impact on drug-addicted offenders

This study examines variables that could predict treatment perseverance and impact for offenders (N = 124) admitted to one of five rehabilitation centers for alcoholics/drug addicts representing different regions of the province of Quebec. Information was collected on time spent in treatment, alcohol/drug use-related problems, motivation to change, criminal profile, subject's perception of judicial pressure, subjective assessment of importance/probability of judicial consequences tied to treatment dropout or substance use, quality of the therapeutic relationship, assessment of client commitment to treatment, and social support. Results indicate that judicial pressure only have impact on retention into treatment for those who are not already sentenced but this "forced" retention is not linked with positive results. The study's limitations are noted.     

Health Impact Assessment--yet another new illusion of efficacy or a truly useful tool for decision-making?

Since 1999, the Canton of Jura has been contributing to international and national efforts towards sustainability. In this context, and under strong political support, people in this Canton have been engaging upon implementation of health impact assessment techniques. This paper describes the main lessons to be learned from this local experience.     

Modulation of Anti-Tumor Necrosis Factor Alpha (TNF-α) Antibody Secretion in Mice Immunized with TNF-α Kinoid

Tumor necrosis factor alpha (TNF-α) blockade is an effective treatment for patients with TNF-α-dependent chronic inflammatory diseases, such as rheumatoid arthritis, Crohn''s disease, and psoriasis. TNF-α kinoid, a heterocomplex of human TNF-α and keyhole limpet hemocyanin (KLH) (TNF-K), is an active immunotherapy targeting TNF-α. Since the TNF-K approach is an active immunization, and patients receiving this therapy also receive immunosuppressant treatment, we evaluated the effect of some immunosuppressive drugs on the generation of anti-TNF-α antibodies produced during TNF-K treatment. BALB/c mice were injected intramuscularly with TNF-K in ISA 51 adjuvant. Mice were also injected intraperitoneally with one of the following: phosphate-buffered saline, cyclophosphamide, methylprednisolone, or methotrexate. Anti-TNF-α and anti-KLH antibody levels were assessed by enzyme-linked immunosorbent assay and the anti-TNF-α neutralizing capacity of sera by L929 bioassay. Our results showed that current treatments used in rheumatoid arthritis, such as methylprednisolone and methotrexate, do not significantly alter anti-TNF-α antibody production after TNF-K immunization. In contrast, the administration of cyclophosphamide (200 mg/kg) after immunization significantly reduced anti-TNF-α antibody titers and their neutralizing capacity.     

CD8(+) T-cell reconstitution in recipients of umbilical cord blood transplantation and characteristics associated with leukemic relapse

Recipients of umbilical cord blood (UCB) transplantation (UCBT) face a high risk of morbidity and mortality related to opportunistic infections (OI) and leukemic relapse. To understand the molecular basis of these UCBT-related complications, the characteristics of UCB-derived antigen-specific CD8(+) T cells were examined in a group of pediatric UCBT recipients. Compared with the UCB graft inoculum and the late post-UCBT period (12-36 months), declining clonal diversity of UCB-derived CD8(+) T cells specific for the Melan-A(26-35) A27L peptide and high frequencies of PD-1-expressing CD8(+) T cells were observed in the first 3 months after UCBT, a period during which OIs are most frequent. The CD8(+) T-cell compartment predominantly comprised CD45RA(+) CCR7(-) terminally differentiated effector-memory T cells until 6 months after UCBT, at which time the polyfunctionality of antigen-specific CD8(+) T cells was reestablished. Finally, the frequency of PD-1(+) CD8(+) T cells was significantly higher in subjects who subsequently experienced leukemic relapse. This study informs the biologic properties of UCB-derived CD8(+) T cells and provides a rationale for the characteristics of UCBT in terms of immune reconstitution and OI. These results also suggest that the elevated frequency of PD-1(+) CD8(+) T cells could be associated with leukemic relapse in pediatric UCBT recipients.     

No loss of chance of diabetic retinopathy screening by endocrinologists with a digital fundus camera

OBJECTIVE

To compare the efficacy of the diabetic retinopathy (DR) screening with digital camera by endocrinologists with that by specialist and resident ophthalmologists in terms of sensitivity, specificity, and level of “loss of chance.”

RESEARCH DESIGN AND METHODS

In a cross-sectional study, 500 adult diabetic patients (1,000 eyes) underwent three-field retinal photography with a digital fundus camera following pupillary dilatation. Five endocrinologists and two ophthalmology residents underwent 40 h of training on screening and grading of DR and detection of associated retinal findings. A κ test compared the accuracy of endocrinologist and ophthalmology resident screening with that performed by experienced ophthalmologists. Screening efficiency of endocrinologists was evaluated in terms of “loss of chance,” i.e., missed diagnoses that required ophthalmologist referrals.

RESULTS

The mean weighted κ of DR screening performed by endocronologists was similar to that of ophthalmology residents (0.65 vs. 0.73). Out of 456 DR eyes, both endocrinologists and ophthalmology residents misdiagnosed only stage 1 DR (36 and 14, respectively), which did not require ophthalmologist referral. There were no significant differences between endocrinologists and ophthalmology residents in terms of diabetic maculopathy and incidental findings except for papillary cupping and choroidal lesions, which were not the main purpose of the study or of the training.

CONCLUSIONS

The endocrinologist with specific training for DR detection using a three-field digital fundus camera with pupillary dilatation can perform a reliable DR screening without any loss of chance for the patients when compared with identical evaluation performed by experienced ophthalmologists.Diabetic retinopathy (DR) is one of the main causes of blindness in industrialized nations (1). The worldwide prevalence of diabetes in adults is estimated to rise to 7.7%, affecting 439 million adults by 2030 (2). In France, the increasing number of patients with diabetes, coupled with the lack of a national screening program, results in a steady rise in the visual handicaps related to the disease (3).Annual screening of DR is recommended as an effective approach to prevent visual loss related to diabetes (4,5). Currently, digital nonmydriatic fundus photography is increasingly used as a method of screening for ophthalmologists worldwide (5–7). According to consensus classifications (4,5), DR at a stage higher than 1 needs further ophthalmological management. Despite these recommendations, only 30% of the diabetic patients in France undergo DR screening each year. Partly, this is due to the lack of ophthalmologists and insufficient awareness about the visual consequences of the disease (3,8). The situation is slowly changing after implementation of telemedical screening networks using digital fundus photography (9–11). Further increase in screening coverage can be achieved with the involvement of allied medical professionals.Since the 1980s, the concept of “loss of chance” has emerged in medicine and law. The misdiagnosis during DR screening can lead to a loss of chance for patients requiring referral to an ophthalmologist for further examinations and management (12,13).Two studies have shown that screening performed by an endocrinologist using an ophthalmoscope (14) and a mydriatic camera (15), respectively, were reliable, although they didn’t evaluate the loss of chance. Furthermore, no endocrinologists’ team approach was evaluated so far.This clinical research trial has been designed to compare the efficacy of the DR screening with digital camera by a team of previously trained endocrinologists (7) with that of residents and specialist ophthalmologists, in terms of sensitivity, specificity and level of “loss of chance.”     

Lymphoid neogenesis in chronic rejection: the murderer is in the house

Although chronic rejection is currently the main cause of long-term allograft failure, its pathogenesis remains elusive, hereby preventing the development of effective therapy. Recent advances in the comprehension of the pathophysiology of chronic inflammatory diseases could shed new light on the pathogenesis of chronic rejection. Lymphoid neogenesis is a mechanism responsible for the progressive organization of chronic inflammatory infiltrates into functional ectopic germinal centers, and has been evidenced recently in various pathological situations sharing a common feature: the failure of the immune response to eradicate the targeted antigen(s). Chronic rejection is such a situation as it results from a sustained alloimmune response against the donor's antigens that are constantly replenished by the grafted tissue. Accordingly, functional ectopic germinal centers develop within chronically rejected organs. This implies that, during chronic rejection, graft is at the same time the target and the site of elicitation of the alloimmune response.