T helper cell type 2 cytokines coordinately regulate immunoglobulin E-dependent cysteinyl leukotriene production by human cord blood-derived mast cells: profound induction of leukotriene C(4) synthase expression by interleukin 4

Human mast cells (hMCs) derived in vitro from cord blood mononuclear cells exhibit stem cell factor (SCF)-dependent comitogenic responses to T helper cell type 2 (Th2) cytokines. As cysteinyl leukotriene (cys-LT) biosynthesis is a characteristic of immunoglobulin (Ig)E-activated mucosal hMCs, we speculated that Th2 cytokines might regulate eicosanoid generation by hMCs. After passive sensitization for 5 d with IgE in the presence of SCF, anti-IgE-stimulated hMCs elaborated minimal cys-LT (0.1 +/- 0.1 ng/10(6) hMCs) and abundant prostaglandin (PG)D(2) (16.2 +/- 10.3 ng/10(6) hMCs). Priming of hMCs by interleukin (IL)-4 with SCF during passive sensitization enhanced their anti-IgE-dependent histamine exocytosis and increased their generation of both cys-LT (by 27-fold) and PGD(2) (by 2. 5-fold). Although priming with IL-3 or IL-5 alone for 5 d with SCF minimally enhanced anti-IgE-mediated cys-LT generation, these cytokines induced further six- and fourfold increases, respectively, in IgE-dependent cys-LT generation when provided with IL-4 and SCF; this occurred without changes in PGD(2) generation or histamine exocytosis relative to hMCs primed with IL-4 alone. None of these cytokines, either alone or in combination, substantially altered the levels of cytosolic phospholipase A(2) (cPLA(2)), 5-lipoxygenase (5-LO), or 5-LO activating protein (FLAP) protein expression by hMCs. In contrast, IL-4 priming dramatically induced the steady-state expression of leukotriene C(4) synthase (LTC(4)S) mRNA within 6 h, and increased the expression of LTC(4)S protein and functional activity in a dose- and time-dependent manner, with plateaus at 10 ng/ml and 5 d, respectively. Priming by either IL-3 or IL-5, with or without IL-4, supported the localization of 5-LO to the nucleus of hMCs. Thus, different Th2-derived cytokines target distinct steps in the 5-LO/LTC(4)S biosynthetic pathway (induction of LTC(4)S expression and nuclear import of 5-LO, respectively), each of which is necessary for a full integrated functional response to IgE-dependent activation, thus modulating the effector phenotype of mature hMCs.     

fMRI evidence that the neural basis of response inhibition is task-dependent

Event-related fMRI was used to investigate the hypothesis that neural activity involved in response inhibition depends upon the nature of the response being inhibited. Two different Go/No-go tasks were compared-one with a high working memory load and one with low. The 'simple' Go/No-go task with low working memory load required subjects to push a button in response to green spaceships but not red spaceships. A 'counting' Go/No-go task (high working memory load) required subjects to respond to green spaceships as well as to those red spaceships preceded by an even number of green spaceships. In both tasks, stimuli were presented every 1.5 s with a 5:1 ratio of green-to-red spaceships. fMRI group data for each task were analyzed using random effects models to determine signal change patterns associated with Go events and No-go events (corrected P< or =0.05). For both tasks, Go responses were associated with signal change in the left primary sensorimotor cortex, supplementary motor area (SMA) proper, and anterior cerebellum (right>left). For the simple task, No-go events were associated with activation in the pre-SMA; the working memory-loaded 'counting' task elicited additional No-go activation in the right dorsolateral prefrontal cortex. The findings suggest that neural contributions to response inhibition may be task dependent; the pre-SMA appears necessary for inhibition of unwanted movements, while the dorsolateral prefrontal cortex is recruited for tasks involving increased working memory load.     

A new low-dose formulation of selegiline: clinical efficacy,patient preference and selectivity for MAO-B inhibition

Summary. Three studies were performed using a fast dissolving formulation of selegiline hydrochloride designed for buccal absorption Zydis Selegiline. The aim of the first study was to compare the therapeutic efficacy of Zydis Selegiline (1.25mg or 10mg) with conventional selegiline hydrochloride tablets conventional selegiline tablets (10mg) in patients with Parkinsons disease (PD) who were previously treated with conventional selegiline tablets as an adjunct to levodopa/dopamine agonist therapy. Patients were observed for 4 weeks to ensure that they were stable. Stable patients (n=197) were then randomised to continue with conventional selegiline tablets 10mg (n=68), or to treatment with Zydis Selegiline 1.25mg (n=64) or Zydis Selegiline 10mg (n=62) for 12 weeks in this randomised, parallel group study. A further aim was to establish the acceptability of Zydis Selegiline compared with conventional selegiline tablets. Patient preference for Zydis Selegiline was also evaluated in a second study, a single-dose, randomised, two-way crossover study conducted in patients with PD (n=148). Patients were stratified by the presence or absence of swallowing and salivation problems and were randomised to either Zydis Selegiline 5mg or a placebo fast-dissolving formulation. In a third study, the degree of potentiation of the tyramine pressor effect following Zydis Selegiline was compared with that following conventional selegiline tablets in healthy volunteers. A total of 24 healthy volunteers were randomised to receive Zydis Selegiline 1.25mg or conventional selegiline tablets 10mg for 14–16 days in an open-label, randomised parallel group study.Both Zydis Selegiline (1.25mg and 10mg) treatments were shown to be therapeutically equivalent to conventional selegiline tablets 10mg based on comparison of mean total Unified Parkinsons Disease Rating Scale (UPDRS) scores. Therapeutic equivalence was defined a priori as the 90% confidence interval (CI) for the difference in total UPDRS scores between groups to lie entirely within the range ±5. The difference (90% CI) in mean adjusted total UPDRS between Zydis Selegiline 1.25mg and conventional selegiline tablets 10mg was –2.50 (–4.84, –0.17), and for Zydis Selegiline 10mg and conventional selegiline tablets 10mg, 0.04 (–2.30, 2.38). For the motor subscores of the UPDRS, differences between adjusted means (90% CI) compared with the conventional selegiline tablets group were: Zydis Selegiline 1.25mg, –2.14 (–3.94, –0.33) and Zydis Selegiline 10mg, –0.90 (–2.70, +0.91). Patients who switched from conventional selegiline tablets to Zydis Selegiline 1.25mg showed a slight improvement in UPDRS scores following 12 weeks of treatment (standard error of difference 1.039; p=0.01).In the single-dose crossover study, most (61%) patients liked Zydis Selegiline 5mg; a significantly greater proportion than the null hypothesis of 50% (p<0.002). However, only 62 patients (46%) indicated that they liked the taste of Zydis Selegiline. Nevertheless, the proportion of patients who preferred Zydis Selegiline (65%) to their usual medication was significantly greater than the null hypothesis of 50% (p<0.001).Similar findings were demonstrated in the 12-week study where a higher proportion of patients who received up to 3 months of treatment indicated a preference for either Zydis Selegiline 1.25mg (90%) or Zydis Selegiline 10mg (86%) over conventional selegiline tablets 10mg. More than 90% of patients found Zydis Selegiline easy to take, with 61% rating it as extremely easy. Most (81%) patients taking Zydis Selegiline 1.25mg liked the taste compared with 45% taking Zydis Selegiline 5mg (in the previous study).Zydis Selegiline did not potentiate the tyramine effect: a pressor effect was elicited after 400mg tyramine both before and after 14 days of treatment with Zydis Selegiline 1.25mg. In contrast, after 14 days treatment with conventional selegiline tablets 10mg, the threshold dose required to elicit the tyramine pressor response was significantly (p<0.0001) reduced from 400mg to 200mg.In summary, Zydis Selegiline at doses of 1.25mg and 10mg was therapeutically equivalent to conventional selegiline tablets 10mg. The Zydis Selegiline formulation was well-liked by all patients, with most preferring Zydis Selegiline 1.25mg to their usual selegiline tablet. Furthermore, Zydis Selegiline was well tolerated and, unlike conventional selegiline tablets, appeared to retain specificity for inhibition of monoamine oxidase type B (MAO-B), since it did not potentiate the pressor response to tyramine.Present address: Cephalon UK Ltd., Surrey Research Park, Guildford, United KingdomPresent address: Safetymednet, Ruscombe, United KingdomPresent address: Oxford Glycosciences (UK) Ltd., Abingdon, United KingdomReceived December 3, 2002; accepted July 23, 2003     

Current pharmacotherapy for hepatitis B infection

Chronic infection with the hepatitis B virus (HBV) affects 350 million people worldwide, or approximately 5% of the global population, and commonly results in cirrhosis and hepatocellular carcinoma. Until recently, the only available treatment was injectable interferon alpha and response rates were suboptimal. Moreover, this expensive and toxic therapy had little applicability in the endemic regions of the world, i.e., Asia and Africa. The realisation that orally available nucleoside and nucleotide agents may effectively control this infection opened a new era in the management of chronic hepatitis B. Oral lamivudine recently became approved for treatment of hepatitis B worldwide. It is free of significant toxicity, improves liver histology and rapidly diminishes HBV DNA levels; lamivudine is expected to become the first-line therapy of choice. Nevertheless, the consistent emergence of lamivudine-resistant variants mandates the need to develop additional therapeutic agents. Adefovir dipivoxil, a nucleotide, and entecavir, a nucleoside agent, are promising new drugs that might eventually be used in combination with lamivudine and therefore reduce the incidence of drug resistance. There is a critical need to advance the research of hepatitis B antiviral agents so that effective combination therapies can become widely available.     

Expression of insulin-like growth factor I by cultured skin substitutes does not replace the physiologic requirement for insulin in vitro

Clinical efficacy of cultured skin substitutes may be increased if their carbohydrate metabolism is optimized by understanding whether endogenous insulin-like growth factor I can substitute for exogenous insulin. Cultured skin substitutes were prepared and incubated at the air-liquid interface for 4 wk in media containing 0.5 or 5 microg per ml insulin, 10 or 50 ng per ml insulin-like growth factor I, or 0 insulin and 0 insulin-like growth factor I (negative control). In situ hybridization showed that the epidermal and dermal cultured skin substitute components express insulin-like growth factor I mRNA throughout the 28 d interval. Immunohistochemistry confirmed the expression of insulin-like growth factor I protein by the human keratinocytes and fibroblasts in cultured skin substitutes. Insulin-like growth factor I at 10 or 30 ng per ml could partially replace insulin in a clonal assay of keratinocyte growth. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays showed significantly higher values in cultured skin substitutes incubated with insulin at incubation days 14 and 28 compared to negative control or the 10 ng per ml insulin-like growth factor I condition. Cultured skin substitutes incubated in 50 ng per ml insulin-like growth factor I had MTT values similar to the insulin-treated cultured skin substitutes at day 14, but were significantly lower by day 28. Light microscopy agreed with MTT data showing that cultured skin substitutes grown with insulin media had multiple layers of nucleated keratinocytes and stratum corneum at days 14 and 28. The negative control and 10 ng per ml insulin-like growth factor I exhibited poor cultured skin substitute epidermal morphology throughout the experiment. In contrast, the cultured skin substitutes in 50 ng per ml insulin-like growth factor I were similar to the insulin-treated cultured skin substitutes at day 14, but by day 28 had deteriorated to resemble the negative control. Bromodeoxyuridine incorporation at day 28 was significantly higher for 5 microg per ml insulin cultured skin substitutes versus all other treatment groups. These data suggest that medium containing 5 microg per ml insulin supports greater physiologic stability in cultured skin substitutes over time, and that expression of insulin- like growth factor I by keratinocytes and fibroblasts in cultured skin substitutes is not sufficient to fully replace the requirement for exogenous insulin in vitro.     

Brief report: cautions against using the Stanford-Binet-IV to classify high-risk preschoolers

OBJECTIVE: To explore concurrent and predictive validity of the Stanford-Binet: Fourth Edition (SB-IV) by comparing scores on the SB-IV with scores from the Battelle Developmental Inventory (BDI) and later achievement scores in preschoolers at risk due to very low birthweight, and/or intraventricular hemorrhage (IVH) and other medical complications. METHODS: At ages 3,4, and 5, 92 preschoolers were tested with the SB-IV and BDI as part of an 8-year early intervention follow-up. RESULTS: The SB-IV and BDI concurrent correlations at ages 3, 4, and 5 were statistically significant (r = .73-.78, p < .0001), as were predictive correlations (r = .58-.85, p < .0001). However, the BDI and SB-IV failed to place the children in the same categories for intervention services. With the BDI as the comparison measure, SB-IV failed to detect 87% of the children who were "delayed" (by BDI) at age 3 and 50% of the "delayed" children at age 5. CONCLUSIONS: Caution is recommended when using the SB-IV to assess high risk for early intervention eligibility.     

Ibandronate reduces osteolytic lesions but not tumor burden in a murine model of myeloma bone disease

We determined the effects of the potent bisphosphonate ibandronate in a murine model of human myeloma bone disease. In this model, bone lesions typical of the human disease develop in mice following inoculation of myeloma cells via the tail vein. Treatment with ibandronate (4 micrograms per mouse per day) significantly reduced the occurrence of osteolytic bone lesions in myeloma-bearing mice. However, ibandronate did not prevent the mice from developing hindlimb paralysis and did not produce a detectable effect on survival. There was no significant effect of ibandronate on total myeloma cell burden, as assessed by morphometric measurements of myeloma cells in the bone marrow, liver, and spleen, or by measurement of serum IgG2b levels. These results support clinical findings that bisphosphonates may be useful for the treatment of myeloma-associated bone destruction, but suggest that other therapies are also required to reduce tumor growth.     

Potential Risk Factors Associated with Thrombocytop in a Surgical Intensive Care Unit

We conducted a retrospective chart review of 193 patients admitted during a 3-month period to determine the frequency of and potential risk factors associated with thrombocytopenia, and the association of acquired thrombocytopenia with length of stay in a surgical-trauma intensive care unit (SICU) and mortality. All records were reviewed beginning 24 hours after admission. Patients were followed for the duration of SICU stay or until death. Data collected and analyzed as potential risk factors for thrombocytopenia were age, gender, admitting diagnosis, classification (trauma, surgical, medical), APACHE II score, medical history, all scheduled drugs with start and stop dates, select laboratory values, arterial or central line placement, and complications. Thrombocytopenia occurred in 25 (13%) patients. These patients were more likely (p<0.05) than those without thrombocytopenia to have the following potential risk factors: presence of a central or arterial line (76% vs 46%, p<0.025), nonsurgical diagnosis (60% vs 37%, p<0.05), diagnosis of sepsis (p<0.001), and administration of phenytoin (p<0.01), piperacillin (p<0.005), imipenem-cilastatin (p<0.001), and vancomycin (p<0.005). A longer SICU stay (mean 21 vs 4.5 days, p<0.05) and increased mortality (16% vs 4%, p<0.05) were significantly associated with thrombocytopenia. Cefazolin administration was significantly associated with nonthrombocytopenia (p<0.05). Factors not associated with thrombocytopenia were age, gender, and administration of histamine₂-receptor antagonists, heparin, enoxaparin, penicillins, ceftazidime, ceftriaxone, chloramphenicol, and amphotericin B. A central or arterial line was the only factor associated with the development of thrombocytopenia in a multiple linear regression analysis (p=0.0003, multiple r=0.2580). Thrombocytopenia is not a common occurrence in the SICU, but is associated with a longer SICU stay and increased mortality.     

Relationship between the chest radiograph, regional lung function studies, exercise tolerance, and clinical condition in cystic fibrosis

This study evaluated the accuracy of the interpretation of the chest film in delineating localised abnormalities of ventilation and perfusion, as well as the overall severity of airways obstruction, exercise tolerance, and clinical condition in children with cystic fibrosis. Radiographic findings in various regions of the chest film were compared with the functional values obtained with regional lung function tests which evaluated the arrival and disappearance of boluses of radioactive nitrogen given by inhalation and infusion. While the more severely affected areas on the chest radiograph were found to correlate with similar regions on the lung function tests, as did overall scores, errors occurred in some cases if the x-ray film alone was used as a judge of regional physiological derangement. In addition the degree of airways obstruction, the exercise tolerance on a cycle ergometer, and clinical grading, each correlated significantly with the radiographic score. We conclude that the chest radiograph is a good indicator of the overall severity of the lung disease and that it correlates well with exercise tolerance and clinical condition in cystic fibrosis.