The pulmonary absorption of aerosolized and intratracheally instilled rhG-CSF and monoPEGylated rhG-CSF

PURPOSE: The objective of this study was to highlight differences in the pulmonary absorption of a monoPEGylated rhG-CSF and rhG-CSF after intratracheal instillation and aerosol delivery. METHODS: Male Sprague Dawley rats (250 g) were anesthetized and intratracheally instilled (IT) with protein solution or were endotracheally intubated and administered aerosol for 20 min via a Harvard small animal ventilator. A DeVilbiss "Aerosonic" nebulizer containing 5 ml of protein solution at approximately 3 mg/ml was used to generate aerosol. The volume of protein solution deposited in the lung lobes was estimated to be approximately 13 microliters after delivery of Tc-99m HSA solutions. The PEGylated proteins consisted of a 6 kDa (P6) or 12 kDa PEG (P12) linked to the N-terminus of rhG-CSF. rhG-CSF also was administered IT in buffers at pH 4 and pH 7 and in dosing volumes ranging from 100 to 400 microliters. Blood samples were removed at intervals after dosing and the total white blood cell counts (WBC) were determined. Plasma was assayed for proteins by an enzyme immuno assay. RESULTS: The plasma protein concentration v. time profiles were strikingly different for aerosol v. IT delivery. The Cmax values for rhG-CSF and P12 after aerosol delivery were greater than found after IT (Aerosol: 598 +/- 135 (ng/ml) rhG-CSF; 182 +/- 14 P12 v. IT: 105 +/- 12 rhG-CSF; 65.9 +/- 5 P12). Similarly, Tmax was reached much earlier after aerosol administration (Aerosol: 21.7 +/- 4.8 (min) rhG-CSF; 168 +/- 31 P12 v. IT: 100 +/- 17 rhG-CSF; 310 +/- 121 P12). Estimated bioavailabilities (F(lung)%) were significantly greater via aerosol delivery than those obtained after IT (Aerosol: 66 +/- 14 rhG-CSF; 12.3 +/- 1.9 P12 v. IT: 11.9 +/- 1.5 rhG-CSF; 1.6 +/- 0.1 P12). An increase in circulating WBC counts was induced by all proteins delivered to the lungs. The rate and extent of absorption of rhG-CSF was not influenced by the pH employed nor the instilled volume. CONCLUSIONS: Estimates of bioavailability are dependent upon the technique employed to administer drug to the lungs. Aerosol administration provides a better estimate of the systemic absorption of macromolecules.     

Functional state of the supraepithelial mucous layer of the digestive tract in mice in the postnatal period after irradiation

It was studied the condition of mucous layer of intestine in mice model experiments after ionizing radiation. It were found out the differences in reaction of intestine on radiation in mice at the age of 55 and 95 days. In mice at the age of 55 days at the whole stretch of intestine was marked increased secretion of the polymeric glycoproteins, whereas in mice at the age of 95 days such alterations were marked at smaller degree. In both groups mice was marked increased secretion of bicarbonate after radiation, that is possible to count as characteristic compensative mechanism.     

SPECT and PET in neurobiology

PET (positron emission tomography) and SPECT (single photon emission computed tomography) are isotopic methods in which the distribution is registered of radiolabelled tracers given in such small amounts that they are without effect on the organism or the organism's disposal of them. Thus, a series of important biological processes in the intact organism can be studied. The methods have been used in many disciplines but in particular for neurobiological research on the brain--e.g., the brain's regional blood circulation and mapping of the brain's functional structure. The methods have also been used in the investigation of glucose and amino acid metabolism in the brain and receptor conditions.     

Neonatal administration of ACTH(1-10) causes genotype-dependent changes in the level of brain monoamines and audiogenic sensitivity in adult CBA and 101/HY mice

We studied the haemodynamic response to cessation of mechanical ventilation and removal of the tracheal tube in 84 patients after coronary artery bypass grafting. Patients were sedated on the ICU with propofol 1-3 mg kg-1 h-1, and randomly allocated to extubation while awake or while still sedated. Systolic and diastolic blood pressures and heart rate increased significantly faster in the awake group as mechanical ventilation was stopped; systolic blood pressure 6.1 (3.0) vs 0.7 (1.8) mm Hg min-1, diastolic blood pressure 2.1 (1.6) vs 0.2 (0.9) mm Hg min-1, heart rate 2.1 (1.7) vs 0.2 (0.5) beats min-2; P < 0.01 in each case. Treatment was required for systolic hypertension during discontinuation of mechanical ventilation in 20 patients (53%) in the awake group and in three patients (7.5%) in the sedated group (P < 0.001). No patient in the sedated group had any new ischaemic ECG changes. Significant new ST segment changes did not occur in the sedated group but were present in five patients in the awake group (P = 0.013), one of whom suffered a perioperative myocardial infarction. Removal of the tracheal tube while patients are still sedated after coronary artery bypass grafting is safe, and reduces the incidences of haemodynamic disturbance and myocardial ischaemia during extubation.     

Recommendations on the use of colony-stimulating factors in children: conclusions of a European panel

During 1996 and 1997 a panel of European haematologists, oncologists, and neonatologists developed specific paediatric guidelines for the use of colony stimulating factors based on published literature and the clinical experience of these specialists within each of 13 countries. Well established indications for use comprise intervention in patients with life-threatening infection, adjunctive therapy post autologous bone marrow transplantation (BMT), mobilization of peripheral blood progenitor cells for autologous BMT, patients with acquired aplastic anaemia on anti-lymphocyte globulin and cyclosporin regimen, and severe congenital neutropenia. Less clear indications include primary prophylaxis to support dose intensification in children with high risk/advanced malignancies, secondary prophylaxis to prevent neutropenia in patients with a history of severe neutropenia, support therapy in cases of poor marrow function following BMT and for deteriorating marrow function following successful BMT, in neonatal sepsis and non infectious neonatal neutropenia, in drug induced neutropenia and in HIV-positive patients. Treatment is generally well tolerated and granulocyte colony stimulating factor appears better tolerated than granulocyte and macrophage colony stimulating factor. Economically colony stimulating factors have not been shown to induce excessive costs for a given patient. CONCLUSION: In general the adult guidelines are applicable to children but additional considerations (aggressive or very progressive childhood neoplasms, specific indications, neonatal use, congenital disorders) must be taken into account.     

Protein folding and protein evolution: common folding nucleus in different subfamilies of c-type cytochromes?

Amino acid sequences of seven subfamilies of cytochromes c (mitochondrial cytochromes c, c1; chloroplast cytochromes c6, cf; bacterial cytochromes c2, c550, c551; in total 164 sequences) have been compared. Despite extensive homology within eukaryotic subfamilies, homology between different subfamilies is very weak. Other than the three heme-binding residues (Cys13, Cys14, His18, in numeration of horse cytochrome c) there are only four positions which are conserved in all subfamilies: Gly/Ala6, Phe/Tyr10, Leu/Val/Phe94 and Tyr/Trp/Phe97. In all 17 cytochromes c with known 3D-structures, these residues form a network of conserved contacts (6-94, 6-97, 10-94, 10-97 and 94-97). Especially strong is the contact between aromatic groups in positions 10 and 97, which corresponds to 13 interatomic contacts. As residues 6, 10 and residues 94, 97 are in (i, i+4) and (i, i+3) positions in the N and C-terminal helices, respectively, the above mentioned system of conserved contacts consists mainly of contacts between one turn of N-terminal helix and one turn of C-terminal helix. The importance of the contacts between interfaces of these helices has been confirmed by the existence of these contacts in both equilibrium and kinetic molten globule-like folding intermediates, as well as by mutational evidence that these contacts are involved in tight packing between the N and C-helices. Since these four residues are not involved in heme binding and have no other apparent functional role, their conservation in highly diverged cytochromes c suggests that they are of a critical importance for protein folding. The author assumes that they are involved in a common folding nucleus of all subfamilies of c-type cytochromes.     

Differential effects of migraine drugs on cerebral blood flow autoregulation

OBJECTIVE: To compare the efficacy and tolerability of mirtazapine and fluoxetine in depressed inpatients and outpatients. METHOD: Patients with a major depressive episode (DSM-III-R), a baseline score of > or=21 on the 17-item Hamilton Rating Scale for Depression (HAM-D), and > or=2 on HAM-D Item 1 (depressed mood) were randomly assigned to a 6-week treatment with either mirtazapine (N=66, 15-60 mg/day) or fluoxetine (N=67, 20-40 mg/day). The upper limit of the mirtazapine dose range was above the dose range approved in the United States (15-45 mg/day). Efficacy was evaluated by the HAM-D, Clinical Global Impressions, the Visual Analogue Mood Rating Scale (VAMRS), and the Quality of Life Enjoyment and Satisfaction Questionnaire (QLESQ). The efficacy analyses were performed on the intent-to-treat group using the last-observation-carried-forward method. RESULTS: Mean total 17-item HAM-D scores at baseline were 26.0 for the mirtazapine- and 26.1 for the fluoxetine-treated group. The decrease from baseline on the HAM-D was larger in the mirtazapine than in the fluoxetine group throughout the treatment period, reaching statistical significance at days 21 and 28. At assessments from day 21 and onward, the absolute difference between the 2 study groups favoring mirtazapine ranged from 3.7 to 4.2 points, the magnitude of difference usually seen between an efficacious antidepressant drug and placebo. Mean dosages at weeks 1-4 were 36.5 mg/day for mirtazapine and 19.6 mg/day for fluoxetine; the respective dosages at weeks 5-6 were 56.3 mg and 35.8 mg. Similar numbers of patients dropped out due to adverse events; tolerability profiles were comparable except for changes in body weight from baseline which were statistically significantly more pronounced in the mirtazapine group compared to the fluoxetine group. CONCLUSION: We found that mirtazapine was as well tolerated as fluoxetine and significantly more effective after 3 and 4 weeks of therapy.