Influence of alkyl chain lengths in dialkylglycerophosphocholines towards phospholipase A2 inhibition in macrophages

Immunocytochemistry using antibodies against various molecular forms of the Ca++ and Zn(++)-binding S100 proteins predominantly labelled astrocytes. However, especially in the neocortex the staining pattern is variable. Methods of tissue preparation have been evaluated with the aim to preserve as much S100 immunoreactivity as possible. Optimal results were obtained after perfusion fixation with 4-5% aldehydes, 0.1 M sodium cacodylate, 0.1% CaCl2, pH 7.3. In such preparations, astrocytes were completely labelled including their lamellar compartments in large parts of the central nervous system. Ca(++)-withdrawal had adverse affects on S100 immunoreactivity. Cryostat sections treated with EDTA-containing solutions before fixation showed that Ca(++)-free S100 can apparently not be fixed to the tissue. Perfusion fixatives containing EDTA resulted in inhomogeneous loss of S100 staining, indicating a differential susceptibility of astrocytic subpopulations. A different type of reduction in S100 immunoreactivity occurred around large neocortical blood vessels. Perivascular defects in immunostaining occasionally appeared even after optimal fixation, but could be regularly provoked by mildly acidic fixation (pH 6.6) or prolonged barbiturate anaesthesia. These defects might be based on S100 release into the cerebrospinal fluid. Presumably under none of the conditions studied can the immunoreactivity of all S100-forms and -fractions be completely preserved in the tissue. However, recommendations are presented for optimizing tissue preparation, to the extent that premortal modifications affecting the stainability of astrocytes may be detected by S100 immunohistochemistry in fixed brain tissue.     

Outcome of Burkholderia (Pseudomonas) cepacia colonisation in children with cystic fibrosis following a hospital outbreak

BACKGROUND: While there are reports on the outcome in adults and teenagers with cystic fibrosis of colonisation with Burkholderia (Pseudomonas) cepacia, there is little information in children. METHODS: In December 1991 only one of 115 children with cystic fibrosis attending a paediatric centre was colonised with B cepacia. Over the next 12 months there was a rapid increase with 23 (20%) becoming colonised; eighteen (79%) of these became colonised in hospital at a time that overlapped with the admission of a B cepacia positive child. Three different bacteriocin types were isolated, with one type (S22/PO) being present in 17 (74%) patients. The outcome for children who became colonised with B cepacia was compared with that in 33 children who continued to be colonised with Pseudomonas aeruginosa alone. RESULTS: Children colonised with B cepacia were older and more poorly nourished than those colonised with P aeruginosa, but did not have poorer pulmonary function. After colonisation, the forced expiratory volume in one second (FEV1) deteriorated between consecutive annual tests, with the average deterioration being greater in those with higher initial levels. Five children with B cepacia died from respiratory failure although none showed a fulminant deterioration. Introduction of segregation measures within hospital led to a dramatic decrease in the number of newly colonised patients. CONCLUSIONS: This study provides further evidence for person-to-person spread of B cepacia and confirms the effectiveness of simple isolation measures in interrupting spread. Colonisation with B cepacia and P aeruginosa in children is associated with a more rapid decline in lung function and a significantly increased mortality compared with cases colonised with P aeruginosa alone.     

Complementary deoxyribonucleic acid cloning and characterization of mSP-10: the mouse homologue of human acrosomal protein SP-10

Complementary DNA encoding the putative mouse homologue for human acrosomal protein SP-10, a candidate contraceptive vaccinogen, was cloned and sequenced. The entire open reading frame (amino acids 18 to 261) of the mouse SP-10 (mSP-10), with the exception of the signal peptide (amino acids 1 to 17), was placed under the influence of inducible T7 RNA polymerase/promoter system to overproduce recombinant protein (re-mSP-10) in Escherichia coli. A six-histidine tag, which was coexpressed at the carboxyl terminus of re-mSP-10, provided the means for purification of re-mSP-10 by immobilized metal chelation affinity chromatography technique. The level of purity of re-mSP-10 thus obtained was determined by 2-dimensional gel electrophoresis to be 98%. Immunoblotting with monoclonal and polyclonal antibodies previously generated against human or baboon SP-10 showed that mSP-10 shared significant antigenic similarity with its primate counterparts. The position of mSP-10 in the mouse genome was next mapped through segregation analysis of an interspecific backcross panel of 96 animals. Acrv1 (assigned gene symbol for mSP-10) was localized in the proximal portion of mouse chromosome 9 in a region that exhibits synteny with human 11q23, the region to which ACRV1 (gene symbol for human SP-10) was previously mapped. These characterizations by combined immunological and gene mapping techniques established the cloned mSP-10 to be the mouse homologue of SP-10.     

Compliance with inhaled asthma medication in preschool children

BACKGROUND: Previous studies have shown poor compliance with regular drug therapy in children and adults with asthma. In preschool children the parents supervise and are responsible for drug administration, but little is known of compliance in this group. In addition, there are few data on the patterns of drug use of inhaled prophylactic asthma therapy or of the relation between compliance and symptom control. A study was undertaken to address these issues with the hypothesis that parental supervision would result in good compliance. METHODS: The subjects were 29 asthmatic children aged 15 months to five years already established on inhaled prophylactic medication delivered through a large volume spacer. The prescribed drug regimens varied between subjects. This was an observational study using an electronic inhaler timer device to record the date and time of each actuation of the aerosol canister. Diary cards were used for parallel recording of symptoms and parentally reported compliance with a drug regimen. RESULTS: Variable and generally poor compliance was demonstrated with a median of 50% of study days with full compliance (subject range 0-94%) and an overall median of 77% of prescribed doses of therapy taken during the study period. No relation was found between frequency of prescribed regimen and good compliance. Day care was associated with poorer compliance. No relation between good compliance and low symptom scores was found. CONCLUSION: Compliance with inhaled prophylactic therapy is poor in preschool children with asthma whose medication is administered under parental supervision.     

Immune suppression therapy in aplastic anemia: influencing factors on response and survival

Calpains are intracellular cysteine proteases activated in a Ca(2+)-dependent manner. Previously, we found that the differentiation of K562 cells induced by 4 beta-phorbol 12-myristate 13-acetate treatment is accompanied by an increase in m-calpain levels and, at the same time, m-calpain becomes localized on the inside of plasma membranes, coated pits, and coated vesicles [Nakamura, M., Mori, M., Morishita, Y., Mori, S. & Kawashima, S. (1992) Exp. Cell Res. 200, 513-522]. We also reported that mu-calpain plays an essential role in morphological changes and membrane fusion of erythrocytes through the degradation of spectrin, a lining protein [Hayashi, M., Saito, Y. & Kawashima, S. (1992) Biochim. Biophys. Res. Commun. 182, 939-946]. Thus, calpains are implicated in endocytosis and/or exocytosis, processes stimulated by Ca2+ and involving intracellular membrane fusion. In this study, we report the biochemical characterization of calpains as components of purified coated vesicles from bovine brain. It was found by Western-blot analysis and chemical cross-linking of proteins that calpains are bound to the membranes of coated vesicles, and not to the coats. The binding of m-calpain to vesicles is Ca(2+)-dependent, while that of mu-calpain is less dependent on the presence of Ca2+. We also identified substrate proteins for calpains in coated vesicles. Upon activation of endogenous calpains, component proteins of coated vesicles such as the clathrin light chain, tubulins, and adaptins, but not the clathrin heavy chain, are highly sensitive to calpain digestion. In the case of exogenously added calpains, low concentrations degraded the same protein components. The degradation pattern differs slightly between added mu-calpain and m-calpain. These results strongly suggest that calpains are involved in the formation of coated vesicles and/or vesicle fusion to endosomes.     

Exposures to patient and personnel in computed axial tomography

Distribution of radiation exposure circumcranially for patients undergoing brain scanning with EMI computed tomographic equipment was measured using thermoluminescent dosimeters. The exposures are found to lie in the range of 1-5 R depending on position relative to tube motion. The maximum exposure of 5 R in CT scanning lies between the estimated exposure of 1.2 R for skull radiography and approximately 10 R for angiographic examination. Measured exposures are reported corresponding to locations of the patients' eyes, thyroid, chest and gonads, and at various locations in the vicinity of the unit.