Granulocyte colony-stimulating factor administration to healthy volunteers: analysis of the immediate activating effects on circulating neutrophils

In four healthy volunteers, we analyzed in detail the immediate in vivo effects on circulating neutrophils of subcutaneous administration of 300 micrograms of granulocyte colony-stimulating factor (G-CSF). Neutrophil activation was assessed by measurement of degranulation. Mobilization of secretory vesicles was shown by a decrease in leukocyte alkaline phosphatase content of the circulating neutrophils. Furthermore, shortly postinjection, Fc gamma RIII was found to be upregulated from an intracellular pool that we identified by immunoelectron microscopy as secretory vesicles. Intravascular release of specific granules was shown by increased plasma levels of lactoferrin and by upregulation of the expression of CD66b and CD11b on circulating neutrophils. Moreover, measurement of fourfold elevated plasma levels of elastase, bound to its physiologic inhibitor alpha 1- antitrypsin, indicated mobilization of azurophil granules. However, no expression of CD63, a marker of azurophil granules, was observed on circulating neutrophils. G-CSF--induced mobilization of secretory vesicles and specific granules could be mimicked in whole blood cultures in vitro, in contrast to release of azurophil granules. Therefore, we postulate that the most activated neutrophils leave the circulation, as observed shortly postinjection, and undergo subsequent stimulation in the endothelial microenvironment, resulting in mobilization of azurophil granules. Our data demonstrate that G-CSF should be regarded as a potent immediate activator of neutrophils in vivo.     

Strategies adopted to manage physical and psychosocial challenges after returning home among people with stroke: A qualitative study

Stroke survivors encounter various physical and psychosocial challenges after hospital discharge. Systematic reviews consistently suggest the importance of self-management in promoting post-stroke recovery. However, stroke survivors’ performance of self-management behaviors after returning home is poorly understood. This study was conducted to explore how stroke survivors manage their life after returning home from the hospital. This was a qualitative study with individual, semi-structured interviews. We recruited a purposive sample of adults who had a first or recurrent ischemic or hemorrhagic stroke and currently lived at home. Participants were asked about their post-stroke experiences, challenges encountered, and strategies adopted for managing post-stroke conditions. Data were transcribed verbatim and analyzed using thematic analysis. A total of 30 stroke survivors (mean age = 61.97 years, SD = 10.20) were interviewed. Most were men (n = 18), married (n = 25), and retired (n = 21). Two-thirds had experienced an ischemic stroke. Five key themes emerged: pursuing lifelong learning to live well after a stroke; reinterpreting unpleasant experiences as new learning opportunities; engaging in life activities to better adapt to post-stroke challenges; being confident in oneself to persevere in self-management behaviors; and continuing to accept the current self and explore the new self. Participants regarded learning as a prerequisite for improving their affected functions and managing uncertainties in recovery. Learning requires self-participation, building self-efficacy and positive outcome expectations, testing and adapting strategies to one''s own health conditions, and engaging in leisure or social activities. These findings will guide future development of interventions for enhancing stroke survivors’ recovery outcomes.     

Mechanism of protein remodeling by ClpA chaperone

ClpA, a newly discovered ATP-dependent molecular chaperone, remodels bacteriophage P1 RepA dimers into monomers, thereby activating the latent specific DNA binding activity of RepA. We investigated the mechanism of the chaperone activity of ClpA by dissociating the reaction into several steps and determining the role of nucleotide in each step. In the presence of ATP or a nonhydrolyzable ATP analog, the initial step is the self-assembly of ClpA and its association with inactive RepA dimers. ClpA-RepA complexes form rapidly and at 0°C but are relatively unstable. The next step is the conversion of unstable ClpA-RepA complexes into stable complexes in a time- and temperature-dependent reaction. The transition to stable ClpA-RepA complexes requires binding of ATP, but not ATP hydrolysis, because nonhydrolyzable ATP analogs satisfy the nucleotide requirement. The stable complexes contain approximately 1 mol of RepA dimer per mol of ClpA hexamer and are committed to activating RepA. In the last step of the reaction, active RepA is released upon exchange of ATP with the nonhydrolyzable ATP analog and ATP hydrolysis. Importantly, we discovered that one cycle of RepA binding to ClpA followed by ATP-dependent release is sufficient to convert inactive RepA to its active form.     

Approach to the patient with recurrent neprolithiasis

Although recurring nephrolithiasis may not be as common as single-episode disease, it poses greater problems to the patient's daily lifestyle and general future health status. The general need for an adequate history, examination, and radiological assessment is acknowledged, but a more intensive investigative and management approach is required. Investigations for secondary causes are paramount and may lead to identification of unusual metabolic abnormalities and specific therapies. Such medical approaches entail consideration of dietary adjustments to lower the urinary excretion of components of the renal stones, pharmacological therapies to modulate urinary constituents and limit renal stone risk, and monitoring efficacy of the therapy over time. This approach will prevent significant deterioration of renal function and other serious metabolic consequences.     

Mycoplasma pneumoniae and Chlamydia pneumoniae in asthma: effect of clarithromycin

STUDY OBJECTIVES: To determine the effect of clarithromycin therapy in patients with asthma. DESIGN: Randomized, double blind, placebo-controlled trial. SETTING: A tertiary referral center. PATIENTS OR PARTICIPANTS: Fifty-five subjects with chronic, stable asthma recruited from the general Denver, CO, community. INTERVENTIONS: Patients underwent airway evaluation for Mycoplasma pneumoniae and Chlamydia pneumoniae by polymerase chain reaction (PCR) and culture, followed by treatment with clarithromycin, 500 bid, or placebo for 6 weeks. MEASUREMENTS AND RESULTS: Outcome variables were lung function, sinusitis as measured by CT, and the inflammatory mediators tumor necrosis factor (TNF)-alpha, interleukin (IL)-2, IL-4, IL-5, and IL-12 messenger RNA (mRNA) measured via in situ hybridization, in airway biopsies, and BAL. Mycoplasma or chlamydia were detected by PCR in 31 of 55 asthmatics. Treatment resulted in a significant improvement in the FEV(1), but only in the PCR-positive subjects (2.50 +/- 0.16 to 2.69 +/- 0.19 L, mean +/- SEM; p = 0.05). This was not appreciated in the PCR-negative subjects (2.59 +/- 0.24 to 2.54 +/- 0.18 L, p = 0.85) or the PCR-positive or PCR-negative subjects who received placebo. Sinus CTs revealed no change in sinusitis with clarithromycin treatment. In situ hybridization revealed no significant difference in baseline airway tissue or BAL-mediator expression between the PCR-positive and PCR-negative subjects. However, the PCR-positive subjects who received clarithromycin demonstrated a reduction in TNF-alpha (p = 0.006), IL-5 (p = 0.007), and IL-12 (p = 0.004) mRNA in BAL and TNF-alpha mRNA in airway tissue (p = 0.0009). The PCR-negative subjects who received clarithromycin only demonstrated a reduction in TNF-alpha (p = 0.01) and IL-12 (p = 0.002) mRNA in BAL and TNF-alpha mRNA in airway tissue (p = 0.004). There were no significant differences in cytokine expression in those subjects who received placebo. CONCLUSIONS: These observations support the hypothesis that clarithromycin therapy improves lung function, but only in those subjects with positive PCR findings for M pneumoniae or C pneumoniae.     

Safety of sputum induction in moderate-to-severe chronic obstructive pulmonary disease

This retrospective study was designed to evaluate the safety and efficacy of a bronchoprotective sputum induction protocol in moderate to severe chronic obstructive pulmonary disease (COPD). Forty-two adults with COPD (FEV1 = 51.7 +/- 3.2% predicted (mean +/- SEM)) under went sputum induction using a protocol designed to minimize hypertonic saline-induced bronchoconstriction. Hypertonic (3%) saline was used for subjects with FEV1 > or = 50%, and normal (0.9%) saline was used for subjects with FEV1 < 50%. Primary outcomes were change in peak flow, FEV1 and oxygen saturation. Mean decline in peak flow during sputum induction was 13.2 +/- 2.1%. FEV1 fell by 11.4 +/- 2.3%, an absolute fall of 0.14 +/- 0.031. Oxygen saturation did not change. A fall in peak flow of > or = 20% reliably predicted a fall in FEV1 of > or = 20%. Thirty-five of 42 subjects (83.3%) produced an acceptable sputum sample. Sputum eosinophil and neutrophil percentages were 2.8 +/- 0.9 and 73.0 +/- 3.0%, respectively, and were not correlated with changes in peak flow, FEV1 or oxygen saturation. A protocol for sputum induction which restricts the use of hypertonic saline based on lung function is both safe and effective in subjects with moderate to severe COPD.     

Exaggerated natriuretic and calciuric responses to hydrochlorothiazide in renal hypercalciuria but not in absorptive hypercalciuria

Patients with hypercalciuria have been reported to have an exaggerated response to hydrochlorothiazide (HCTZ), implying a renal tubular defect in solute reabsorption. To determine whether this disturbance is generalized or unique to a particular pathogenetic type of hypercalciuria, we measured the increments in urinary sodium (delta Na), calcium (delta Ca), and magnesium after a 100-mg dose of oral HCTZ in 10 normal subjects and 31 patients with different types of hypercalciuric nephrolithiasis. Eleven patients with renal hypercalciuria had significantly greater delta Na (P less than 0.005) and delta Ca (P less than 0.005) than the normal subjects. Ten patients with absorptive hypercalciuria and 10 patients with fasting hypercalciuria without parathyroid stimulation had delta Na and delta Ca indistinguishable from those of normal subjects. In all groups, urinary HCTZ and basal 24-h urinary Na did not differ. The results suggest that the unique natriuretic and calciuric responses to HCTZ occur only in renal hypercalciuric patients with secondary hyperparathyroidism. The data support a renal tubular defect in renal hypercalciuric in contrast to other diagnostic categories of hypercalciuric nephrolithiasis.     

Elevated levels of transforming growth factor-beta(1) in serum of patients with stable bronchiectasis

Bronchiectasis is a chronic inflammatory and infective airway disease characterized by irreversible dilatation of the bronchi and persistent purulent sputum. Transforming growth factor-beta(1) (TGF-beta(1)) has been found to be increased in the lungs or bronchoalveolar lavage fluid of patients with inflammatory lung diseases. However, little is known on the serum TGF-beta(1) levels in patients with bronchiectasis. We aimed to determine the serum TGF-beta(1) concentrations in 95 patients with stable bronchiectasis (63 women; mean+/-sd age, 58.9+/-14.1 years) and 68 control subjects (23 women; 48.9+/-12.8 years) by ELISA, and to correlate with clinical parameters. The serum TGF-beta(1) levels were significantly higher in bronchiectatic patients compared with control subjects (median [range], 1812.5 pg/ml [1226.4-4114.5 pg/ml] vs. 1342.4 pg/ml [940.3-2371.7 pg/ml]; P<0.001). There was, however, no correlation between serum TGF-beta(1) levels with FEV(1) (% predicted), FVC (% predicted), 24h sputum volume, the number of bronchiectatic lung lobes or total white blood cell count (P>0.05). Our findings support previous indications that TGF-beta(1) may contribute to bronchiectatic airway inflammation. Further studies on the potential mechanisms and pathogenesis implications of this elevation should also be pursued in future.