Diffuse axonal injury induced by simultaneous moderate linear and angular head accelerations in rats

Diffuse axonal injury (DAI) is one of the most common and important pathologic features of human traumatic brain injury (TBI), accounting for high mortality and development of persistent post-traumatic neurologic sequelae. Although a relatively high number of therapies have been shown to be effective in experimental models, there are currently few treatments that are effective for improving the prognosis of clinical DAI. A major reason is the failure of current models to validly reproduce the pathophysiological characteristics observed after clinical DAI. In the present study, we employed a specially designed, highly controllable model to induce a sudden rotation in the coronal plane (75 degrees rotation at 1.6x10(4) degrees/s) combined with lateral translation (1.57 cm displacement at 3.4x10(2) cm/s) to the rat's head. We were interested in discovering whether the combined accelerations could reproduce the pathophysiological changes analogous to those seen in human DAI. The axonal injury as assessed with amyloid protein precursor (APP) as a marker was consistently present in all injured rats. The commonly injured brain regions included the subcortical regions, deep white matter, corpus callosum and brain stem. The evolution of APP accumulations in brain sections depicted the detailed progression of axonal pathology. Ultrastructural studies gave further insights into the presence and progression of axonal injury. All injured rats exhibited transient physiological dysfunction, as well as immediate and dramatic neurological impairment that still persisted at 14 days after injury. These results suggest that this model reproduced the major pathophysiological changes analogous to those observed after severe clinical TBI and provides an attractive vehicle for experimental brain injury research.

Implication of ethanol wet-bonding in hybrid layer remineralization

During mineralization, unbound water within the collagen matrix is replaced by apatite. This study tested the null hypothesis that there is no difference in the status of in vitro biomimetic remineralization of hybrid layers, regardless of their moisture contents. Acid-etched dentin was bonded with One-Step with ethanol-wet-bonding, water-wet-bonding, and water-overwet-bonding protocols. Composite-dentin slabs were subjected to remineralization for 1-4 months in a medium containing dual biomimetic analogs, with set Portland cement as the calcium source and characterized by transmission electron microscopy. Remineralization was either non-existent or restricted to the intrafibrillar mode in ethanol-wet-bonded specimens. Extensive intrafibrillar and interfibrillar remineralization was observed in water-wet-bonded specimens. Water-overwet specimens demonstrated partial remineralization of hybrid layers and precipitation of mineralized plates within water channels. The use of ethanol-wet-bonding substantiates that biomimetic remineralization is a progressive dehydration process that replaces residual water in hybrid layers with apatite crystallites.

Failure of a glass ionomer to remineralize apatite-depleted dentin

Remineralization of demineralized dentin lesions adjacent to glass-ionomer cements (GICs) has been reported in the literature. This study tested the hypothesis that a strontium-based GIC can remineralize completely demineralized dentin by nucleation of new apatite crystallites within an apatite-free dentin matrix. Human dentin specimens were acid-etched, bonded with Fuji IX(GP), and immersed in a calcium-and-phosphate-containing 1.5X simulated body fluid (SBF) for 1-4 months. Polyacrylic acid and polyvinylphosphonic acid biomimetic analogs were added to the SBFs to create 2 additional remineralization media. Specimens were processed by transmission electron microscopy (TEM). No apatite deposition could be identified in the completely demineralized dentin in any of the specimens immersed in the 3 remineralization media, despite TEM/EDX evidence of diffusion of ions specific to the strontium-based GIC into the demineralized dentin. The hypothesis was rejected; mineral concentration alone is not a sufficient endpoint for assessing the success of contemporary remineralization strategies.

Direct imaging of surface plasmon resonances on single triangular silver nanoprisms at optical wavelength using low-loss EFTEM imaging

Using low-loss energy-filtering transmission electron microscopy (EFTEM) imaging, we map surface plasmon resonances (SPRs) at optical wavelengths on single triangular silver nanoprisms. We show that EFTEM imaging combining high spatial sampling and high energy resolution enables the detection and for the first time, to the best of our knowledge, mapping at the nanoscale of an extra multipolar SPR on these nanoparticles. As illustrated on a 276.5 nm long nanoprism, this eigenmode is found to be enhanced on the three edges where it exhibits a two-lobe distribution.

[Treatment of 2 children with mucopolysaccharidosis by allogeneic hematopoietic stem cell transplantation]

OBJECTIVE

Mucopolysaccharidosis(MPS) is a congenital hereditary disease. Only a few patients with this disease can be controlled by enzyme replacement therapy. Most of them are short of effective interference. To exploit the effect of treatment with allogenic hematopoietic stem cell transplantation, two children were treated with the transplantation.

METHODS

The two patients included a 23 month MPS-IH and an 18 month old MPS-VI at the time of transplantation. Busulfan of 20 mg/kg plus 200 mg of Cyclophosphamide were used as the conditioning regimen. Peripheral stem cells were collected from a 9/10 high resolution matched unrelated donor and a matched sibling carrier donor, respectively. The heart and lung were affected in the patient with MPS-IH. Medium obstructed pulmonary impairment was found by pulmonary function test at the time of transplantation. Medium mitral valve countercurrent and patent ductus arteriosis(PDA) were found by Doppla examination.

RESULTS

The number of hematopoietic stem cells was comparative between the two donors with total nucleated cells and CD34+ cells of 11 x 10(8)/kg and 17 x 10(8)/kg, and 7.6 x 10(6)/kg and 7.2x 10(6)/kg respectively. Neutrophil engrafted at day 11. The process of transplantation in the MPS-VI patient went smoothly with grade II graft versus host disease(GVHD) briefly and only 1 U RBC and 2 U platelet were transfused. For the MPS-IH patient, the process of transplantation was tough with platelet reaching to 20 x 10(9)/L till day 40 and 5 U RBC and 7 U platelet were transfused during transplantation. Grade III GVHD was resolved by steroid, mycophenolate mofetil (MMF) and CD25 antibody. Pneumonia recurred 3 times with 2 times rescued by trachea intubation and mechanical ventilation because of accompanying acute heart failure. At day 14 the lymphocytes in both patients were 100% from donors as evidenced by short tandem repeat-PCR(STR-PCR). MPS associated enzyme activity was increased to 70 nmol/h.mg and 66 nmol/h.mg at 3 month and still remained 50.9 nmol/h.mg and 44.5 nmol/h.mg at 2 years post transplantation. Till now the 2 patients have been followed up for 25 months and 28 months with good general condition. The cardiac and pulmonary functions have improved obviously in the MPS-IH patient. The cornea became clear in this patient.

CONCLUSION

Allogeneic hematopoietic stem cell transplantation is an effective measure to treat patient with MPS-IH and MPS-VI. Transplantation at earlier stage of age can decrease transplant related complications. It requires longer time follow up for observing the clinical effects for these patients.

Signalling pathways for transactivation by dexmedetomidine of epidermal growth factor receptors in astrocytes and its paracrine effect on neurons

BACKGROUND AND PURPOSE

Stimulation of astrocytes by the alpha(2)-adrenoceptor agonist dexmedetomidine, a neuroprotective drug, transactivates epidermal growth factor (EGF) receptors. The present study investigates signal pathways leading to release of an EGF receptor ligand and those activated during EGF receptor stimulation, and the response of neurons to dexmedetomidine and to astrocyte-conditioned medium.

EXPERIMENTAL APPROACH

Phosphorylation of ERK(1/2) was determined by western blotting and immunocytochemistry, and phosphorylation of EGF receptors by immunoprecipitation and western blotting. mRNA expression of fos family was measured by RT-PCR.

KEY RESULTS

Pertussis toxin (0.2 microg ml(-1)) an inhibitor of betagamma subunit dissociation from Galpha(i) protein, and GF 109203X (500 nM), a protein kinase C inhibitor, abolished ERK(1/2) phosphorylation. PP1 (10 microM), inhibiting Src kinase and GM 6001 (10 microM), an inhibitor of Zn-dependent metalloproteinase, abolished ERK(1/2) phosphorylation by dexmedetomidine (50 nM), but not that by EGF (10 ng ml(-1)), showing Src kinase and metalloproteinase activation during the first stage only; AG 1478 (1 microM), an inhibitor of the EGF receptor tyrosine kinase, abolished ERK(1/2) phosphorylation. Dexmedetomidine-induced EGF receptor phosphorylation was prevented by AG 1478, GM 6001, PP1 and GF 109203X and its induction of cfos and fosB by AG 1478 and by U0126 (10 microM), an inhibitor of ERK phosphorylation, indicating downstream effects of ERK(1/2) phosphorylation. EGF and conditioned medium from dexmedetomidine-treated astrocytes, but not dexmedetomidine itself, induced ERK phosphorylation in primary cultures of cerebellar neurons.

CONCLUSIONS AND IMPLICATIONS

Dexmedetomidine-induced transactivation pathways were delineated. Its paracrine effect on neurons may account for its neuroprotective effects.

Influences of MxA gene -88 G/T and IFN-gamma +874 A/T on the natural history of hepatitis B virus infection in an endemic area

The influence of human genetics on the natural history of hepatitis B virus (HBV) infection may be diminished in endemic areas because infection at a young age predisposes to chronic HBV infection. The present study aimed to address this issue through the determination of the influences of single nucleotide polymorphisms (SNPs) of myxovirus resistence-1 (MxA) -88 G/T and interferon (IFN)-gamma +874 A/T on the natural history of HBV infection in endemic regions. One hundred adult patients with self-limiting HBV infection (positive for both anti-HBs and anti-HBc) and 340 adult patients with persistent HBV infection were recruited from southern China, an endemic area with an HBsAg carrier rate of 17.8%. SNPs of MxA -88 G/T and interferon (IFN)-gamma +874 A/T were typed using a protocol based on competitively differentiated polymerase chain reaction. A highly significant difference in the distribution of MxA -88 G/T was observed between those with persistent and self-limiting HBV infections. The latter displayed a lower frequency of the GG genotype (41.0% vs. 52.9%, P = 0.036) and a higher frequency of the TT genotype (16.0% vs. 2.4%, P = 0.000), compared to patients with persistent infection. These differences were not gender- or age-specific. However, a significant distribution difference of IFN-gamma +874 A/T was not observed. Between two groups of patients, respectively, the distribution frequencies of the AA genotype (65.0% vs. 72.8%, P = 0.139) and the TT genotype (2.0% vs. 1.2%, P = 0.894) were found. These results suggest that MxA gene -88 G/T and IFN-gamma +874 A/T behave differently in endemic HBV infections. Further study is necessary to clarify the influences of human genetics on endemic HBV infections.

Parameters controlling the gene-targeting frequency at the Sphingomonas species rrn site and expression of the methyl parathion hydrolase gene

AIMS

To investigate the key parameters controlling the exogenous methyl parathion hydrolase (MPH) gene mpd-targeting frequency at the ribosomal RNA operon (rrn) site of Sphingomonas species which has a wide range of biotechnological applications.

METHODS AND RESULTS

Targeting vectors with different homology lengths and recipient target DNA with different homology identities were used to investigate the parameters controlling the targeting frequency at the Sphingomonas species rrn site. Targeting frequency decreased with the reduction of homology length, and the minimal size for normal homologous recombination was >100 bp. Homologous recombination could succeed even if there were 3-4% mismatches; however, targeting frequency decreased with increasing sequence divergence. The Red recombination system could increase the targeting frequency to some extent. Targeting of the mpd gene to the rrn site did not affect cell viability and resulted in an increase of MPH-specific activity in recombinants.

CONCLUSIONS

Targeting frequency was affected by homology length, identity and the Red recombination system. The rrn site is a good target site for the expression of exogenous genes.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work is useful as a foundation for a better understanding of recombination events involving homologous sequences and for the improved manipulation of Sphingomonas genes in biotechnological applications.

Pre-clinical studies and phase I clinical trial of the anti-CD22 immunotoxin CAT-3888 (BL22) for pediatric acute lymphoblastic leukemia (ALL)

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Background: ALL is the most common childhood malignancy. Although highly curable, therapy is associated with multiple toxicities and ALL remains the most frequent cause of pediatric cancer mortality. Most ALL is CD22+ and we evaluated the anti-CD22 immunotoxin RFB4(dsFv)-PE38 (BL22 or CAT-3888) in the treatment of pediatric ALL. Methods: In vitro cytotoxicity was assessed on blasts from 42 children with CD22+ ALL. In vivo studies were performed using a xenograft model (SCID mouse - EU1 human ALL cell line). A pediatric phase I trial of CAT-3888 was initiated. Results: CAT-3888 induced in vitro cytotoxicity against most ALL samples (median IC50 9.8 ng/ml). A dose response was observed in murine xenografts with significant prolongation of leukemia free survival (p<0.05). 18 subjects (15 ALL, 3 lymphoma; 3 - 22 years of age) were treated on a Phase I trial at doses of 10 - 40 mcg/kg QOD for 3 - 6 doses with cycles repeated every 21 - 28 days. Treatment was well tolerated and no dose limiting toxicity was seen. Pharmacokinetics were influenced by disease burden and T1/2 showed an inverse relationship to marrow blasts (r2=0.5) consistent with rapid drug binding by CD22+ cells. All subjects were heavily pre-treated and had progressive high burden disease at the time of treatment. Transient clinical activity was observed in 16 of 18 subjects as evidenced by decreased peripheral blast count (8), decreased marrow infiltration (3), decreased extramedullary disease (2), increased platelet count (2), increased neutrophil count (1), increased reticulocyte count (1), improved PET scan (1), decreased tumor-associated pain (2), and/or peripheral blast count stabilization (3). A dose response was apparent with 4 of 9 (44%) achieving stable disease at or above doses of 30 mcg/kg. Conclusions: The majority of pediatric ALL blasts are highly sensitive in vitro to CAT-3888 at concentrations far below clinically achievable levels. CAT-3888 is well tolerated in pediatric patients and activity has been seen in most subjects treated on the phase I trial. CD22 represents a relevant target for pediatric ALL. A new higher affinity anti-CD22 immunotoxin (HA22 or CAT-8015) is in development.

No significant financial relationships to disclose.

Phase II randomized trial of docetaxel plus cetuximab or bortezomib in patients with advanced NSCLC and performance status (PS) 2—CALGB 30402

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Background: There is no standard treatment for patients (pts) with advanced NSCLC and PS 2. Docetaxel (D) is active and well tolerated on a weekly schedule. Cetuximab (C) and Bortezomib (B) are new agents with activity in NSCLC. We explored these two new combinations in PS 2 pts. Methods: In a multi-center randomized phase II trial, untreated pts with advanced NSCLC and PS 2 were randomized to D 30 mg/m2 d1,8,15 q. 28 days in combination with either C 400 mg/m2 week 1 then 250 mg/m2 weekly, or B 1.6 mg/m2 d1,8,15 q. 28 days for 4 cycles. Pts with CR/PR/SD were allowed to continue C or B until PD. The study was non-comparative and the primary endpoint was progression-free survival (PFS) rate at 6 months. The trial had a type I error of 0.0746 and power of 0.9 to differentiate a 6-mo PFS of <20% vs. >42%. Results: 64 pts were enrolled between 7/05 and 9/06. 5 were ineligible and 3 never received protocol treatment. Results are reported for 55 pts (27 D+C; 28 D+B). Most pts had stage IV adenoCa and 13% had brain metastases. Median age was 70 (range, 35–88) and 65% were male. Response: 10.5% for D+C and 13.6% for D+B. Median PFS was 3.1 mo for D+C and 1.8 mo for D+B. PFS rates at 4 mo (data not yet mature for 6-mo): 33% and 28%, respectively. Median survival: 3.8 mo for D+C and 3.3 mo for D+B. Gr 3/4 hematologic toxicity was 17% in both arms. Gr 3/4 non-heme toxicities were 44% in D+C and 36% in D+B arm. 5 pts died of treatment-related toxicities (3 D+C; 2 D+B). Conclusions: These results confirm the poor prognosis associated with a PS of 2. Based on our preliminary analysis, neither combination produced results that justify further research in this subset of patients. The treatment of PS 2 patients with advanced NSCLC remains a vexing problem and new approaches are urgently needed.

No significant financial relationships to disclose.

Phase II randomized study of dose-dense docetaxel (Doc) and cisplatin (Cis) every two weeks with pegfilgrastim (Pfil) and darbepoetin alfa (Darb) with and without the chemoprotector BNP7787 in patients with advanced non-small cell lung cancer (NSCLC): CAL

7617

Background: We sought to explore the toxicity, feasibility, and response rate of dose-dense Doc and Cis with growth factor support without [A] and with [B] a novel chemoprotector in patients with NSCLC. Methods: Patients with measurable disease, stage IIIB (effusion) or IV, performance status (PS) 0–1, no prior chemotherapy, and adequate organ function were eligible. Treatment with Doc 75 mg/m2 ? Cis 75 mg/m2 both IV over 1 hr day 1 with Darb 200 mcg SC day 1 and Pfil 6 mg SC day 2 randomized to without/with BNP before Cis was repeated every other week (1 cycle = 2 weeks) for up to 6 cycles. Response was determined after 3 and 6 cycles. Because of anticipated neurotoxicity (NT), the primary statistical endpoint was to differentiate between grade =2 NT rates of 30% in [A] and 10% in [B]: 90% power, two-tailed p<0.10, 76 patients per arm. Feasibility was prospectively defined as febrile neutropenia in <10% of patients and =1 treatment delay per cycles 1–3 and 4–6 in <20% of patients. Objective response rates of >35% were required to merit further investigation. Results: Between 8/04 and 3/06, 160 patients were enrolled but 5 never started therapy and 4 were ineligible: male/female, 99/52; white/black/other, 126/23/2; median age 62 (range, 30–88); PS 0/1, 69/82; stage IIIB/IV 14/137; [A]/[B], 76/75 well balanced. Sensory/motor/either NT grade =2 occurred in 28/14/32% on [A] and 19/19/29% on [B]. The incidence of febrile neutropenia was 1%. Treatment was delayed in cycles 1–3/cycles 4–6 in 3/3 patients in [A] and 1/5 patients in [B]. Completion rates for 3/6 cycles were 87/51% in [A] and 84/52% in [B]. By intent to treat, complete/partial response rates were 4/46% in [A] and 3/47% in [B]. Median estimated overall/progression-free survival times are10/6 months in [A] and 11/6 months in [B]. Overall, grade 3+4 neutropenia and thrombocytopenia occurred in =10% and anemia in 12% of patients. Non-hematologic toxicity was mild. Six deaths were thought to be treatment related. Conclusions: This dose-dense treatment regimen is feasible, tolerable, and worthy of further investigation in NSCLC. BNP did not result in significant protection from NT.

No significant financial relationships to disclose.

Depolarization-induced, glutamate receptor–mediated, and transactivation-dependent extracellular-signal regulated kinase phosphorylation in cultured cerebellar granule neurons

Depolarization of 7-8-day-old mouse cerebellar granule neurons in primary cultures, a glutamatergic preparation, by elevation of the extracellular potassium ion concentration ([K+]e) to 45 mM induces an increase of phosphorylation of extracellular-signal regulated kinase 1 and 2 (ERK1/2) at two time periods: 20 min and 60 min after the [K+]e increase. This effect can be mimicked by 5 min of exposure to 50 microM glutamate, suggesting that ERK1/2 phosphorylation in response to the depolarization is brought about by the resulting glutamate release. This concept is supported by the observation that the K+ -mediated stimulation of phosphorylation at both times is inhibited by MK-801, an NMDA antagonist, and by CNQX, an AMPA/kainate antagonist. These antagonists also inhibit the response to glutamate. Both increases in ERK1/2 phosphorylation are also inhibited by GM 6001 (a metalloproteinase inhibitor, preventing 'shedding' of growth factors), by AG 1478 (a receptor tyrosine kinase inhibitor, preventing epidermal growth factor [EGF] receptor activation), and also partly by heparin (inactivating heparin-binding epidermal growth factor [HB-EGF]), suggesting transactivation of epidermal growth factor receptors (EGFR). Transactivation is an intracellular/extracellular signal transduction pathway in which release from receptor- or depolarization-stimulated cells of EGFR ligand(s) (including HB-EGF), catalyzed by a metalloproteinase, stimulates receptor tyrosine kinases on the same (an autocrine effect) or adjacent (a paracrine effect) cells. The expression of HB-EGF as well as of transforming growth factor-alpha (TGF-alpha), two of the EGFR ligands, in the cells was confirmed by reverse transcription polymerase chain reaction, and the only partial inhibition by heparin suggests that both of these EGFR agonists are involved. Such a transactivation may play a major role in glutamate-mediated signaling and plasticity.

Chronic ethanol feeding alters the epithelial cell proliferation and apoptosis in rat gastric mucosa

We developed a chronic drinking rat model to investigate the long-term effects of ethanol feeding on cell proliferation and apoptosis in rat stomach. Adult male Sprague-Dawley (SD) rats received either an isocaloric control or drinking water containing 6% (v/v) ethanol as their only water intake for 1, 3, 7, 14 and 28 days. At the end of each feeding period, animals were sacrificed and the stomach was dissected for the sample preparation. The cell proliferation and apoptosis in gastric mucosa of rats in different groups were analyzed by flow cytometer, immunohistochemistry and computer image analysis. In the flow cytometric study, compared with the control, the cell apoptosis in gastric mucosa of the rats was enhanced during the exposure to the ethanol in 3rd to 28th day. Otherwise the cell proliferation was increased in 3rd to 14th days, and decreased in 28th days, respectively. The results were confirmed by immunohistochemistry and computer image analysis studied. This finding suggested that short-term chronic adequate alcohol intake may enhance the cell turnover of gastric mucosa. Long-term stimulus with the low concentration ethanol may cause the impairment of the cell turnover function of the gastric mucosa and may be one of the mechanisms underlying the gastric pathology associated with alcohol abuse.