Oral maintenance clinical trial with miglustat for type I Gaucher disease: switch from or combination with intravenous enzyme replacement

Enzyme replacement therapy (ERT) with imiglucerase reduces hepatosplenomegaly and improves hematologic parameters in Gaucher disease type 1 within 6-24 months. Miglustat reduces organomegaly, improves hematologic parameters, and reverses bone marrow infiltration. This trial evaluates miglustat in patients clinically stable on ERT. Tolerability of miglustat and imiglucerase, alone and in combination, pharmacokinetic profile, organ reduction, and chitotriosidase activity were assessed. Thirty-six patients stable on imiglucerase were randomized into this phase II, open-label trial. Statistically significant changes from baseline were assessed (paired t test) on primary objectives with secondary analyses on biochemical and safety parameters. Liver and spleen volume were unchanged in switched patients. No significant differences were seen between groups regarding mean change in hemoglobin. Mean change in platelet counts was only significant between miglustat and imiglucerase groups (P = .035). Chitotriosidase activity remained stable. In trial extension, clinical endpoints were generally maintained. Miglustat was well tolerated alone or in combination. Miglustat's safety profile was consistent with previous trials; moreover, no new cases of peripheral neuropathy were observed. Gaucher disease type 1 (GD1) parameters were stable in most switched patients. Combination therapy did not show benefit. Findings suggest miglustat could be an effective maintenance therapy in stabilized patients with GD1.     

The Two-Component System CprRS Senses Cationic Peptides and Triggers Adaptive Resistance in Pseudomonas aeruginosa Independently of ParRS

Cationic antimicrobial peptides pass across the outer membrane by interacting with negatively charged lipopolysaccharide (LPS), leading to outer membrane permeabilization in a process termed self-promoted uptake. Resistance can be mediated by the addition of positively charged arabinosamine through the action of the arnBCADTEF operon. We recently described a series of two-component regulators that lead to the activation of the arn operon after recognizing environmental signals, including low-Mg²⁺ (PhoPQ, PmrAB) or cationic (ParRS) peptides. However, some peptides did not activate the arn operon through ParRS. Here, we report the identification of a new two-component system, CprRS, which, upon exposure to a wide range of antimicrobial peptides, triggered the expression of the LPS modification operon. Thus, mutations in the cprRS operon blocked the induction of the arn operon in response to several antimicrobial peptides independently of ParRS but did not affect the response to low Mg²⁺. Distinct patterns of arn induction were identified. Thus, the responses to polymyxins were abrogated by either parR or cprR mutations, while responses to other peptides, including indolicidin, showed differential dependency on the CprRS and ParRS systems in a concentration-dependent manner. It was further demonstrated that, following exposure to inducing antimicrobial peptides, cprRS mutants did not become adaptively resistant to polymyxins as was observed for wild-type cells. Our microarray studies demonstrated that the CprRS system controlled a quite modest regulon, indicating that it was quite specific to adaptive peptide resistance. These findings provide greater insight into the complex regulation of LPS modification in Pseudomonas aeruginosa, which involves the participation of at least 4 two-component systems.     

Development of resistance in wild-type and hypermutable Pseudomonas aeruginosa strains exposed to clinical pharmacokinetic profiles of meropenem and ceftazidime simulated in vitro

In this study we investigated the interplay of antibiotic pharmacokinetic profiles and the development of mutation-mediated resistance in wild-type and hypermutable Pseudomonas aeruginosa strains. We used in vitro models simulating profiles of the commonly used therapeutic drugs meropenem and ceftazidime, two agents with high levels of antipseudomonal activity said to have different potentials for stimulating resistance development. During ceftazidime treatment of the wild-type strain (PAO1), fully resistant mutants overproducing AmpC were selected rapidly and they completely replaced wild-type cells in the population. During treatment with meropenem, mutants of PAO1 were not selected as rapidly and showed only intermediate resistance due to the loss of OprD. These mutants also replaced the parent strain in the population. During the treatment of the mutator P. aeruginosa strain with meropenem, the slowly selected mutants did not accumulate several resistance mechanisms but only lost OprD and did not completely replace the parent strain in the population. Our results indicate that the commonly used dosing regimens for meropenem and ceftazidime cannot avoid the selection of mutants of wild-type and hypermutable P. aeruginosa strains. For the treatment outcome, including the prevention of resistance development, it would be beneficial for the antibiotic concentration to remain above the mutant prevention concentration for a longer period of time than it does in present regimens.     

Impaired uptake of apoptotic cells into tingible body macrophages in germinal centers of patients with systemic lupus erythematosus

OBJECTIVE: To investigate the fate of apoptotic cells in the germinal centers (GCs) of patients with systemic lupus erythematosus (SLE). METHODS: Lymph node biopsy specimens obtained from 7 SLE patients with benign follicular hyperplasia, 5 non-SLE patients with benign follicular hyperplasia (non-SLE), 5 patients with malignant follicular lymphoma, and 3 patients with dermatopathic lymphadenitis were stained with monoclonal antibodies against macrophages (CD68) and follicular dendritic cells (CR2/CD21). TUNEL staining and transmission electron microscopy were performed to detect apoptotic cells. Confocal microscopy was used to evaluate the in vivo capacity of tingible body macrophages to remove apoptotic cell material. RESULTS: In a subgroup of patients with SLE, apoptotic cells accumulated in the GCs of the lymph nodes. The number of tingible body macrophages, which usually contained engulfed apoptotic nuclei, was significantly reduced in these patients. In contrast to what was observed in all controls, TUNEL-positive apoptotic material from SLE patients was observed to be directly associated with the surfaces of follicular dendritic cells (FDCs). CONCLUSION: Our findings suggest that in a sub-group of SLE patients, apoptotic cells are not properly cleared by tingible body macrophages of the GCs. Consequently, nuclear autoantigens bind to FDCs and may thus provide survival signals for autoreactive B cells. This action may override an important control mechanism for B cell development, resulting in the loss of tolerance for nuclear antigens.     

Is there a correlation between degree of splenomegaly,symptoms and hypersplenism? A study of 218 patients with Gaucher disease

Despite the prevalence of splenomegaly as a sign in many disorders, there have been no studies that correlate the degree of organomegaly with the symptoms generally ascribed to splenic enlargement. The degree of splenomegaly was compared with five overt symptoms of mechanical displacement, i.e. chronic abdominal pain, abdominal discomfort, early satiety, pain while lying on the side, or attacks of acute (colicky) left upper quadrant pains. We have also employed splenomegaly as seen in Gaucher disease as a paradigm to determine whether there is a correlation between the degree of splenomegaly and the parameters of hypersplenism. Although there was a statistically significant correlation between degree of splenomegaly and blood counts, this proved to be clinically negligible. Surprisingly, there was also no correlation between degree of splenomegaly and any of symptoms investigated.     

Spontaneous intramural hematoma of the esophagus

Spontaneous intramural hematoma of the esophagus (SIHE) is a rare condition, usually presenting with severe acute chest pain. Vomiting, dysphagia, odynophagia, and hematemesis may appear later. We herein report a case of this disease in a patient treated with low doses of aspirin, and review the literature for possible etiologies for this condition. In addition, we compare the utility of the various diagnostic modalities in this uncommon condition.     

First description of CTX-M beta-lactamase-producing clinical Escherichia coli isolates from Egypt

We studied the presence of β-lactamases with an extended spectrum of activity in clinical Escherichia coli isolates from Cairo, Egypt. Forty-six E. coli isolates were collected from patients with urinary tract infections at a university hospital in 2001. Phenotypic characterisation identified a very high extended-spectrum β-lactamase (ESBL) rate of 60.9%. Pulsed-field gel electrophoresis and plasmid profiles revealed eight different clonal groups. All ESBL producers were polymerase chain reaction-positive for bla_TEM and bla_CTX-M genes. Within the CTX-M family, three different enzymes, CTX-M-14, CTX-M-15 and CTX-M-27, were found. The ESBL producers carried multiple plasmids and further plasmid-encoded resistances. In several strains, genes for up to six aminoglycoside-modifying enzymes were detected. A linkage to fluoroquinolone resistance was not observed. This study confirms the high rate of ESBLs in Egypt and further demonstrates the worldwide spread of genes coding for CTX-M enzymes in clinical isolates.     

Brain-derived neurotrophic factor induces a rapid dephosphorylation of tau protein through a PI-3 Kinase signalling mechanism

The microtubule-associated protein tau is essential for microtubule stabilization in neuronal axons. Hyperphosphorylation and intracellular fibrillar formation of tau protein is a pathology found in Alzheimer's disease (AD) brains, and in a variety of neurodegenerative disorders referred to as 'taupathies'. In the present study, we investigated how brain-derived neurotrophic factor (BDNF), an extracellular factor that is down-regulated in AD brains, affects tau phosphorylation. BDNF stimulation of neuronally differentiated P19 mouse embryonic carcinoma cells resulted in a rapid decrease in tau phosphorylation, at phosphorylation sites recognized by Tau 1, AT 8, AT 180 and p 262-Tau antibodies. K 252 a, a tyrosine receptor kinase (Trk) inhibitor, attenuated this dephosphorylation event, suggesting that BNDF activation of TrkB is responsible for the tau dephosphorylation. In addition, BDNF had no affect on tau phosphorylation in the presence of wortmannin, a PI-3 Kinase inhibitor, or lithium, a GSK 3 beta inhibitor, suggesting that these two kinases are part of the signaling transduction cascade leading from TrkB receptor activation to tau dephosphorylation. These results suggest a link between a correlate of AD, decrease in BDNF levels and an AD pathology, tau hyperphosphorylation.