Synthesis and Evaluation of <Superscript>99m</Superscript>Tc-Labelled Monoclonal Antibody 1D09C3 for Molecular Imaging of Major Histocompatibility Complex Class II Protein Expression

Purpose  

It is known that major histocompatibility complex class II protein HLA-DR is highly expressed in B-cell lymphomas and in a variety of autoimmune and inflammatory diseases. Therefore, a radiolabelled fully humanized IgG4 monoclonal antibody (mAb) can provide useful prognostic and diagnostic information. Aims of the present study were to radiolabel an anti-HLA-DR mAb with technetium-99m and to evaluate its binding specificity, tissue distribution and targeting potential.     

Serum triiodothyronine levels and inflammatory cytokine production capacity

Increasing evidence suggests that pro-inflammatory cytokines are at play in lowering peripheral thyroid hormone levels during critical illness. Conversely, thyroid hormones have been suggested to enhance production of inflammatory cytokines. In view of these considerations, we hypothesized a mutual association between triiodothyronine and pro-inflammatory cytokines. Therefore we evaluated the relation between both circulating and induced inflammatory markers and serum thyroid function parameters in the Leiden 85-plus Study. We found that higher circulating levels of inflammatory markers were associated with lower levels of free serum triiodothyronine. In turn, higher serum free triiodothyronine levels were related to higher production capacity of pro-inflammatory cytokines after stimulation with lipopolysaccharide. By combining in vivo and ex vivo data, we were able to demonstrate for the first time the existence of a potential feedback mechanism between thyroid function and immune production capacity. We conclude that maintenance of normal thyroid function might be important for a preserved immune response in elderly human populations.     

Nonagenarian Siblings and Their Offspring Display Lower Risk of Mortality and Morbidity than Sporadic Nonagenarians: The Leiden Longevity Study

OBJECTIVES: To compare the risk of mortality of nonagenarian siblings with that of sporadic nonagenarians (not selected on having a nonagenarian sibling) and to compare the prevalence of morbidity in their offspring with that of the offsprings' partners.
DESIGN: Longitudinal (mortality risk) and cross-sectional (disease prevalence).
SETTING: Nationwide sample.
PARTICIPANTS: The Leiden Longevity Study consists of 991 nonagenarian siblings derived from 420 Caucasian families, 1,365 of their offspring, and 621 of the offsprings' partners. In the Leiden 85-plus Study, 599 subjects aged 85 were included, of whom 275 attained the age of 90 (sporadic nonagenarians).
MEASUREMENTS: All nonagenarian siblings and sporadic nonagenarians were followed for mortality (with a mean±standard deviation follow-up time of 2.7±1.4 years and 3.0±1.5 years, respectively). Information on medical history and medication use was collected for offspring and their partners.
RESULTS: Nonagenarian siblings had a 41% lower risk of mortality ( P <.001) than sporadic nonagenarians. The offspring of nonagenarian siblings had a lower prevalence of myocardial infarction (2.4% vs 4.1%, P =.03), hypertension (23.0% vs 27.5%, P =.01), diabetes mellitus (4.4% vs 7.6%, P =.004), and use of cardiovascular medication (23.0% vs 28.9%, P =.003) than their partners.
CONCLUSION: The lower mortality rate of nonagenarian siblings and lower prevalence of morbidity in their middle-aged offspring reinforce the notion that resilience against disease and death have similar underlying biology that is determined by genetic or familial factors.     

Factors associated with poor outcomes in patients with lupus nephritis

The objective of this study was to identify the factors associated with important clinical outcomes in a case-control study of 213 patients with lupus nephritis. Included were 47% Hispanics, 44% African Americans and 9% Caucasians with a mean age of 28 years. Fifty-four (25%) patients reached the primary composite outcome of doubling serum creatinine, end-stage renal disease or death during a mean follow-up of 37 months. Thirty-four percent African Americans, 20% Hispanics and 10% Caucasians reached the primary composite outcome (P < 0.05). Patients reaching the composite outcome had predominantly proliferative lupus nephritis (WHO classes: 30% III, 32% IV, 18% V and 5% II, P < 0.025) with higher activity index score (7 +/- 6 versus 5 +/- 5, P < 0.05), chronicity index (CI) score (4 +/- 3 versus 2 +/- 2 unit, P < 0.025), higher baseline mean arterial pressure (MAP) (111 +/- 21 versus 102 +/- 14 mmHg, P < 0.025) and serum creatinine (1.9 +/- 1.3 versus 1.3 +/- 1.0 mg/dL, P < 0.025), but lower baseline hematocrit (29 +/- 6 versus 31 + 5%, P < 0.025) and complement C3 (54 +/- 26 versus 65 + 33 mg/dL, P < 0.025) compared to controls. More patients reaching the composite outcome had nephrotic range proteinuria compared to controls (74% versus 56%, P < 0.025). By multivariate analysis, CI (hazard ratio [95% CI] 1.18 [1.07-1.30] per point), MAP (HR 1.02 [1.00-1.03] per mmHg), and baseline serum creatinine (HR 1.26 [1.04-1.54] per mg/dL) were independently associated with the composite outcome. We concluded that hypertension and elevated serum creatinine at the time of the kidney biopsy as well as a high CI are associated with an increased the risk for chronic renal failure or death in patients with lupus nephritis.     

Gab1, SHP2, and protein kinase A are crucial for the activation of the endothelial NO synthase by fluid shear stress

Fluid shear stress enhances NO production in endothelial cells by a mechanism involving the activation of the phosphatidylinositol 3-kinase and the phosphorylation of the endothelial NO synthase (eNOS). We investigated the role of the scaffolding protein Gab1 and the tyrosine phosphatase SHP2 in this signal transduction cascade in cultured and native endothelial cells. Fluid shear stress elicited the phosphorylation and activation of Akt and eNOS as well as the tyrosine phosphorylation of Gab1 and its association with the p85 subunit of phosphatidylinositol 3-kinase and SHP2. Overexpression of a Gab1 mutant lacking the pleckstrin homology domain abrogated the shear stress-induced phosphorylation of Akt but failed to affect the phosphorylation or activity of eNOS. The latter response, however, was sensitive to a protein kinase A (PKA) inhibitor. Mutation of Gab1 Tyr627 to phenylalanine (YF-Gab1) to prevent the binding of SHP2 completely prevented the shear stress-induced phosphorylation of eNOS, leaving the Akt response intact. A dominant-negative SHP2 mutant prevented the activation of PKA and phosphorylation of eNOS without affecting that of Akt. Moreover, shear stress elicited the formation of a signalosome complex including eNOS, Gab1, SHP2 and the catalytic subunit of PKA. In isolated murine carotid arteries, flow-induced vasodilatation was prevented by a PKA inhibitor as well as by overexpression of either the YF-Gab1 or the dominant-negative SHP2 mutant. Thus, the shear stress-induced activation of eNOS depends on Gab1 and SHP2, which, in turn, regulate the phosphorylation and activity of eNOS by a PKA-dependent but Akt-independent mechanism.     

Basal cerebral blood flow is dependent on the nitric oxide pathway in elderly but not in young healthy men

OBJECTIVE: Brain perfusion is tightly regulated over a wide range of blood pressures by local regulation of cerebral blood flow (CBF). Ageing is associated with impaired CBF and impaired nitric oxide mediated vasodilator responses. The role of nitric oxide in the regulation of basal CBF in young and older subjects was investigated, using the nitric oxide synthase inhibitor L-NMMA as pharmacological tool. METHODS: We used a gradient echo phase-contrast magnetic resonance imaging technique to investigate the role of nitric oxide in the regulation of cerebral blood flow in young (25+/-7.1 years; n=8) and old (78+/-6.6 years; n=7) volunteers. The study was performed in a double-blinded fashion and consisted of two study days. On one day the effects of the intravenously infused L-NMMA on CBF and blood pressure was measured and on the other day the effects of a matching placebo. RESULTS: Basal CBF was significantly lower in old compared to young subjects (590+/-20 vs 704+/-20 ml/min), while the cerebral vascular resistance (CVR) levels were significantly higher (0.15+/-0.01 (arbitrary units) vs 0.12+/-0.01, respectively). Infusion of L-NMMA significantly increased mean arterial pressure in both groups (2.8+/-1.2 mmHg; p=0.02 in the young and in the old subjects 5.6+/-1.1 mmHg; p<0.001). Infusion of L-NMMA significantly decreased CBF (49+/-12 ml/min; p<0.001) and increased CVR (0.02+/-0.004; p<0.001) in the old subjects but did not significantly influence cerebral circulation in the young subjects. CONCLUSION: We conclude that compared to young subjects, in old people CBF is impaired, and dependent on the intactness of the nitric oxide pathway.     

Relevance of underlying disease and bacterial vacA and cagA status on the efficacy of Helicobacter pylori eradication

AIM: To study the effects of Helicobacter pylori associated diseases and the bacterial vacA and cagA statuses on the efficacy of H. pylori eradication. METHODS: A prospective study in a consecutive series of outpatients of a gastroenterological institution and of a primary practice. A series of 146 H. pylori positive patients with peptic ulcer disease (PUD; n = 40) or nonulcer dyspepsia (NUD; n = 106) were evaluated. H. pylori vacA genotpyes and cagA status were determined directly in gastric biopsy specimens by polymerase chain reaction. The patients were treated with triple-therapy regimens consisting of a proton pump inhibitor and two antibiotics twice daily for 7 days. Reevaluation of H. pylori was determined 4-5 weeks later by endoscopy or 13C urea breath test. RESULTS: 123 patients completed the study. In 8 patients, colonization with two or more H. pylori strains was found. The overall cure rate was 84.6% (104/123). The eradication rates were significantly higher in patients with PUD (94.4%, 34/36) than in those with NUD (81.6%, 71/87; p < 0.05). In patients with cagA-positive H. pylori strains, the eradication rate was 89.0% (73/82) as compared with 78.8% (26/33) in those with cagA-negative strains (p = 0.15). The vacA genotype had no effect on the efficacy of H. pylori eradication. CONCLUSION: Using 1-week triple-therapy regimens, treatment of H. pylori infection is more effective in patients with PUD than in those with NUD.