Drug development strategies for asthma: in search of a new paradigm

The spiraling costs of asthma treatment seem set to continue rising, given the equivocal performance of the latest generation of specific anti-inflammatory drugs in trials in adult asthmatics. We argue that the continuation of this trend is inevitable unless there is a substantial realignment of entrenched drug development policy in the pharmaceutical industry and a parallel shift in licensing policy by regulatory authorities to encourage the development of drugs capable of halting the progression from acute to chronic asthma when the disease first manifests in childhood. The theoretical framework for such an approach, including proof-of-principle data from studies in children with early-stage disease and a range of candidate drugs, already exists. What is needed is informed debate on the risks versus potential benefits of this approach.     

Karyotypic evolution in Ph-positive chronic myeloid leukemia in relation to management and disease progression

In a prospective study of 32 patients with chronic myeloid leukemia the frequency of chromosome abnormalities in addition to the Philadelphia chromosome (Ph) increased when the disease progressed. Before metamorphosis, 10 patients (31%) had developed additional abnormalities. Such abnormalities were present in three of them at the time of diagnosis; in the other seven, they were detected late in the chronic phase. New clonal abnormalities heralded or accompanied a more malignant phase of the disorder, usually a blastic leukemia. During metamorphosis, 78% of the patients had additional abnormalities, which in 68% of these cases comprised at least one of +8, +22q- or i(17q). Clones with additional abnormalities disappeared in eight cases, either spontaneously or in association with cytostatic therapy during the chronic or blastic phase. Involvement of chromosome #8, usually in the form of a trisomy, was found in 7 of 12 patients treated with busulfan, but was not found in any of the 10 hydroxyurea-treated patients, of whom 8 were splenectomized early during the chronic phase. Cells from the spleen, obtained by fine needle aspiration or splenectomy were cytogenetically examined in 18 cases during the chronic phase, but abnormalities in addition to the Ph were noted in only one patient, who was examined in the late chronic phase. The same abnormalities were present in bone marrow cells of this patient.     

Somatotopic organization along the central sulcus, for pain localization in humans, as revealed by positron emission tomography

Regional cerebral blood flow was measured with positron emission tomography (PET) in six healthy volunteers at rest and during experimentally induced, sustained cutaneous pain on the dorsum of the right hand or on the dorsum of the right foot. Pain was inflicted by intracutaneous injection of capsaicin, providing a mainly C-fibre nociceptive stimulus. Statistical analysis showed significant activations along the central sulcus (SI) area when comparing pain in the hand to pain in the foot. Separate comparison of both pain states to a baseline revealed different locations along the central sulcus for hand pain and foot pain. The encountered differences are consistent with what is previously known about the somatotopics of non-painful stimuli. When comparing painful stimuli to baseline, the contralateral anterior cingulate gyrus, the ipsilateral anterior insular cortex and the ipsilateral prefrontal cortex were implicated. The results are consistent with an involvement of SI in the spatial discrimination of acute cutaneous pain. Received: 17 October 1996 / Accepted: 12 May 1997     

Long-term safety of once-daily budesonide in patients with early-onset mild persistent asthma: results of the Inhaled Steroid Treatment as Regular Therapy in Early Asthma (START) study.

BACKGROUND: The Inhaled Steroid Treatment as Regular Therapy in Early Asthma (START) study is a worldwide, randomized, prospective study to investigate early intervention with inhaled corticosteroids in recent-onset mild persistent asthma. OBJECTIVE: To evaluate the safety and tolerability of long-term treatment with once-daily budesonide therapy in patients with mild persistent asthma. METHODS: Patients aged 5 to 66 years with mild persistent asthma for fewer than 2 years and no previous regular corticosteroid treatment received budesonide or placebo once daily for 3 years, in addition to their usual asthma therapy. The daily budesonide dose was 200 microg for children younger than 11 years and 400 microg for those 11 years or older. RESULTS: Overall, 7,221 patients were included in the safety analysis, and a total of 21,520 adverse events were reported (10,850 in the budesonide group and 10,670 in the placebo group). The most commonly reported events included respiratory infections, rhinitis, pharyngitis, bronchitis, viral infections, and sinusitis. The number of deaths and serious adverse events were similar for children and adults in both treatment groups. Fewer asthma-related serious adverse events were reported with budesonide (162) compared with placebo (276). Oral candidiasis was reported more frequently with budesonide (1.2%) than with placebo (0.5%); the frequencies of other adverse effects previously reported to be associated with inhaled corticosteroids (psychiatric disorders, skin disorders, and allergic reactions) were similar. CONCLUSIONS: Three-year treatment with budesonide once daily (200 or 400 microg) is safe and well tolerated in children and adults with newly detected mild persistent asthma.     

Non-isotropic noise correlation in PET data reconstructed by FBP but not by OSEM demonstrated using auto-correlation function

Background  

Positron emission tomography (PET) is a powerful imaging technique with the potential of obtaining functional or biochemical information by measuring distribution and kinetics of radiolabelled molecules in a biological system, both in vitro and in vivo. PET images can be used directly or after kinetic modelling to extract quantitative values of a desired physiological, biochemical or pharmacological entity. Because such images are generally noisy, it is essential to understand how noise affects the derived quantitative values. A pre-requisite for this understanding is that the properties of noise such as variance (magnitude) and texture (correlation) are known.     

Platelet monoamine oxidase activity in Down's syndrome

The activity of platelet monoamine oxidase in Down's syndrome cases was significantly lower than that of controls. This difference was found for both males and females, and with tyramine, tryptamine and β-phenethylamine as substrate. The K_m values of the monoamine oxidase towards tryptamine as substrate from controls and Down's syndrome patients were similar.